geekhack Projects > Making Stuff Together!

What does the nipple need to work?

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dotancohen:
I can solder, but I'm no EE. Supposing that one were to acquire a laptop keyboard with a nipple mouse, could it be made operable with a desktop? I can worry about physically modding it into position where I need it, but it is the electrical connections that I worry about. It is not a simple USB connector, but does it internally work as USB? Is the controller onboard, I would just need to wire it correctly?

Example:
http://www.ebay.com/itm/IBM-Lenovo-Thinkpad-X60-X61-Keyboard-42T3499-39T7234-39T7265-42T3531-42T3499-/310394276008?_trksid=p4340.m1986

Thanks!

Zwi:
Although I've always wondered the same I think it would just be simpler to get something like this

mkawa:
the short answer is that it needs an encoder connected to a controller that presents it as a usb mouse.

basically, a trackpoint is a strain gauge that has two analog signals coming from it. one of those is a direction and the other is strain (the amount of force present in that direction). those signals need to be digitally encoded, and then a micro needs to present those to a host device over usb as a 2d position (which is basically what the USBHID mouse driver wants)

Djuzuh:
But if you take your nipple out of another keyboard off, you may have the controller already present, and reuse this one.

mkawa:
so there was a great thread on this in the archived mods forum, but unfortunately all the pictures were gone. thankfully i have an SSK II with TP I can pull apart to show you how it's usually wired up, but the basic idea is that the strain gauge and the encoder are on one chip, and then that has a flex cable that wires it to the main keyboard and mouse controller, which presents a PS/2 mouse to the host device.

i believe this is how it's wired up on all the modern lenovos as well. the flex cable ends in a ZIF, but if someone were to reverse engineer it, i bet interfacing with it and providing a usb mouse could be engineered into a gp micro platform like the teensy or arduino boards..

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